SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3af14ac9a90e284d3cfc87817b0b1ebd74b0fb88c81d2b522869292273a2a461' 
  AND token = 'yiMrJ9tjh3XCpBHr1lZfb8uTIB7QJb6lE580zcaFQ8o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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