SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6aee2b81e0597450288c2dd0c3fdda2ecb8527cf170eb8fd28b273348c7136a0' 
  AND token = 'Glq8VJ+V4TTkwCzZ+WHyUNO6XSdY55shPQaJjQcUEDY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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