SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5243842b72437c8f09db2b716b6d143cead7abff02af801384ced5a2a242cb66' 
  AND token = 'zfbejmDz+Yoavy5fR6HlylTGXagxOavKDfB44bBSDdA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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