SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd49910738a6d58dab25e026173303dfb5856b94b32c1d457044a7701c48cbaa' 
  AND token = '3hLWXqx0V8Uly2Y1ZjZ3pxXjTRpyA++yWUctKz6BNZI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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