SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f0e8093cef375305699ebf4622f8001d248e80f8acfa2547e3f153b814df6fc7' 
  AND token = 'rz3uqJJLeietIChJYJLfWrjxsr+Wp9VSOVUf6IfzzFs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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