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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '671a6fff6f61259252e8c8d46f2cd6b12d01c3f277b4ee6d0866cac872f67472' 
  AND token = 'e5kCTlOfO0qpboIQ8vygNgghceFbtBeU3azYrrrIevk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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