SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'f8ce498f9f0b07e8a98c466e42e99dea53c6cde79ca21c74957250a2abca1972' 
  AND token = 'luemA7gR6ZnFLuWwkHHMtZ0qZAQSk6ctnsTGkO1vLVQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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