SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a17e275f5ef5f118258003a224a0daab7e4fd19202bb115ffaac26de931a7fa7' 
  AND token = 'QUQmTqWUVNKsASYF2A1VqDRw+F5p5rqe0wGfGBRPEfo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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