SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd2a27ee3a417384cfeba7d20ffc441952cbfce4267fec6313b77e9ae84b36397' 
  AND token = 'r6PNltfwICBrrkt89QZvJyfq5eYyaHSCVgrGFYZRtyU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00057

JSON explain

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