SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8363f77f2b285ff0450a3761f7c79f4a2048b4edf9817066e5a81cd4f3c5309a' 
  AND token = 'tF68xueHaJdwX+ZAIrpjPB9SpqDGNZ/omS5eeMjMqXQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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