SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c2c3402b757751f11664895b746f5eca4953f4ed19ead964d032ff90674c78eb' 
  AND token = 'oJkF0d61jX2F2X1gxQWRkpYhZybxC1n6DQSVf6qE4P4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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