SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '4402de48ece44a67039d520c022f40a6c326829ac75417e26623f76b98d576a9' 
  AND token = '0MM+It5WRg6LdckDTzOJkHQy3uqGFdXbZSYctfWvlQU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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