SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '379f56b9e4bded73caa58f846067198369495078c1551712e01605ef63e95b1e' 
  AND token = 'Bkox58D9pCrOk136sPiPemJ+g05sEce260xuTaDcJ+A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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