SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b7795df5fe89b36e7be8849500494388a5fcfb642ca3e6fdf1be298dbdb7953' 
  AND token = '4wykehp5mfpWCBm7S5NzqyyaSy3XrolWtSwaqMHzmLU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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