SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '44addcc005aa6994f862a0072f483a47718eee9b621e489100d102b7b465cacb' 
  AND token = '/GRSR3ERFZIhjNzmT4XQpQDqBBdt4i+nXO0xL8vVbDA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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