SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e6cbdbb962cdb703dceb57de1d6f91000d4179c82eac5c477b3aabfef164a0d' 
  AND token = '3gwUueIGD3PIEsiej9daen0reN7dsSBkPBUEgpCfqKM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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