SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '425097285bbdbc0bdf4ac8ad1a8e13a397981987e35c8d98d381080ccf74c292' 
  AND token = 'ZfDaRvtXXrG8YdHYVvqqgPsAHhVpPCIuURU1ogBE0Hk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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