SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '92110687738b6ec08783f4786bb117ebd95c4e1e5e13fc3ba41b7e62db43cdb9' 
  AND token = 'K91f5bJxAUx/3qCCMQUiHxTdq+2bQPZSZRiactbwnqg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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