SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '296fb48a990531c40e9320730acd0f91f332b36f4db00692699407e590fe0ebd' 
  AND token = 'qzaMFNmTJHVhHXIuR82YiF0vnrHBoO5jwI2KeSUmXz8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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