SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a4a3b249743575cdb911f53ce1ffa06bf8bf97ad39f97e69681477ca9bd2dec6' 
  AND token = 'e4SFZqP39ERO1MTsu6cerQsjQdIYCDvbe7QRxmR4ysk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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