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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c7635910576b6ccf3e3fd52c03b58ad5ce2320dd4bde8d7baf17bf8d64f0d7ee' 
  AND token = 'guosp/Wm+U/X6MyraID8M2a8XgdEWH4t3pTQRRr6sfc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}