SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0f42dc17b93d867ef02085df01c9c4b61d14753b487baec1ad9cab1fa6a0ecf7' 
  AND token = 'MZBU8AKIWox0UKekU7sVMMLJGw6ie3gbEG5ZQRRskms=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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