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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f7f79e6ef6da8fc6a5222bfa8b705df2a8737d9e38bcb5eb43c6b5ccd6f903b6' 
  AND token = 'x9yLR5msd1/DiUGLNtdYR3LZ+53VdQUq0YM+L5vPaXs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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