SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '534268bd1c2141dbc43b79d8e3be17c2e136fcd9db03ab478a064d4ad3265903' 
  AND token = '+Kf9paDzOfQyOBXYOUfLXINI7QWw2NjBHiz5Ly6Ka+A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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