SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5827d313871c2862491f8d653126eaf66800b240be84a598076b000167ae9b0d' 
  AND token = 'y/ffjScj+uCfYrFyyMw42YUIstF5Hf/n+OpJ5sYRjI8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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