SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'e0258c3107bb6947bc55544b9be5e789486ee6e7a92f329c207daf7380c79c49' 
  AND token = '4XSfhfQ21mQ/wzuFyUHD+b6nYNvJBCM2orq62lM11dE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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