SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e72e84f2201a407a9d9b7b3ab3094afbbce0b97739f3754a942cbade6529aa8b' 
  AND token = 'gUrzXtkfpj0UhXhlJ8S9BNxRSRGPlsBBKTHZaOT0xHY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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