SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '258c3931876fb9563577b3b8449fc5d4416315d870a2cb076f21105fb4e0f1c4' 
  AND token = 'Zwsd0z3ctQOBH7jg4epoE/roqtKy409hDuaR+ogLkpw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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