SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c0c383757642f4a4ee8325147813a866f74fb7e936a637049e5c04c2f4d8748' 
  AND token = 'ntTcvQw+PbF/ed7JwKzlyMUBAjmilmAO+m0VPeGfyNI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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