SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c9e5424011537fefc5e0234538210cc528f067d1ae36c98c3d40231a4b4cb211' 
  AND token = 'IUJ7L07EBSOVPmI5103ZNrpujL2Ol9wX/l0dM+BXA9o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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