SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '3de8c393c48347c933700765478615f335364ec41a570aabcf112355fcf5f58e' 
  AND token = 'OJWzBZqC2aIXnmbDpsBFgphrpEj+g84y09vT8i0rZOk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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