SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '818132795ec6a829bbd3a9648c2765a643e04e5489c7c0e3e897c2c0f6f37c25' 
  AND token = 'U0gsT/UiZFkV7T+37ZoRXHsv30GoMjjkoq6HqoL6zmA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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