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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '21f7e0a8b3db7e1ff485cc7db927cbb34cf753e51d130dea53a81c52e6ec22fb' 
  AND token = 'Jjiw0ObCtt1kqE7OYLf6z/8pDNZ8HKDa9CvN6ImRJj8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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