SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e7b7599b2173f3d8ba318da98a5c2020e897e68161cd0ad0f746e20808b8fcca' 
  AND token = 'Vqm0is5CJvdIbQnhRPCJTXKTAkgVJzgQa7ZFtSI09ZI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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