SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b04d19494754638da51dbc483402d5bf866f04531dc2a37739e94e33e30e7299' 
  AND token = 'lvhZ73EXceoXm2I5DyLibHUHSvrwSqnwjniaDUT2AlE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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