SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '868503befc2ffab6c51d0b1149a66b864894105933333e184f87b28afa5d9b40' 
  AND token = '7fQ7gkFlarvZP2Mq+GohgWnYjnByc3hSFQWzvk9Mq6I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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