SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '7ebf5ec639b289474f28c9d577861c7da285351c948287c07d6fd1b4d38745e4' 
  AND token = 'RUpuJWrufghaRThLM3xcBYRw0vXjtPBKWBA7u2m/yL4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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