SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '34c153a532ec7a854b404b417da513f94e9c1a926424016bf72cd767e19b93b7' 
  AND token = 'G99/SNXTCrBtDVjly5okA5znqLJLgDwmMzW1rbIPTW4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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