SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'cf38adacee503aae2368d4d07c54554a4774e2825eb039d1718f2c54af29e5ea' 
  AND token = 'qFms6j5ItjN1DTxVOClUq+2isobRzfVe7995K9kFejo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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