SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3e5fa2b49865f5d3708484489726515d5b2a03153959da7995136be6edef96f6' 
  AND token = 'viUWnSlm0WvuMWsvd3YIwgWskvKjqwpMQRFb1aZVeK4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00099

JSON explain

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