SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '47a6f741ffdef8a03488f23a1d6a346fa6013f89bab2b3931e6c5f7adef00b77' 
  AND token = 'K+o/pEtIMASoVgak4k/PPwVi+uBqJTGXnCh9cMgI4rk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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