SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b1c859302f495a5d2dad9d4549366f94d7abc3f80604058ac93817297df6ce6d' 
  AND token = 'eaCCM/MszHEaOUMo8sFHUwzDOSOCQtZovqKdTVKhRug=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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