SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '4d6b4da876c8c6ed8ec5689df3115a406116ab6f18c125731f47620125dc2c14' 
  AND token = 'R/iucI1zoThKWxggLwYRjU3irKGRfjMdTnWgozXnj7k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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