SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '58c4f7f83337ea133d33df896bd4177af1a8908ac468889c976077a79b6d1088' 
  AND token = 'WhkcPXvXR22odNWWPrkCpJkC690cwGRzikjDYqkhze0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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