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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c2c9fe44846de1eeb60d6840531e5b781020ef9eb0e38326d0c5ff27909ff18' 
  AND token = 'qmRr0y+iNqOXrd9CvSvC+9+SoZ+6FeexisQLR/QKZk8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}