SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cff5e95ccbe01e8eb754d1d75dc35942adc77650e9d14bc178ccea3c4b70c121' 
  AND token = 'lOIOuq8kZ4SvNIE8sZAhP8J5bv0vZolAxdMjbjJjfxw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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