SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '739afdf696f2307642420d723fed5c1218be975c82be5751eb9882305b2c146f' 
  AND token = 'CjuBfxdVLIW8saSQK/os6UuB4QgjtsiBVyz/aefVTKA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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