SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af051d2a351822ebd81442ce4a1d6a4f7b39439eed7e179657558705466284a9' 
  AND token = 'mzqZr+G997o0tCn7WafYhoL6EJI7qxl/8vCpn00T6qY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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