SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '93c84607f37c4023c706bb6660efd80ed7508ac0fe9658e3d488686cb5d21d90' 
  AND token = '9cq4TMieSpG6lCpiTj9bzXBYjar+3tgEgAOMWL7Wut4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}