SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0fc187b44f59971b3bbdc1baffe5ba6a30ba33a031f086b7261b8a69948105b4' 
  AND token = '+DsRzEGUQrmzBhPwdRWNKf5AGIu4MfT78dD9OJiqQgA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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