SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c46da419dd6ab7dbbed635bc2651c681d4e4bf159ca0ea474493a7ce18483281' 
  AND token = 'nZsCpJ5UHSrN89B2JRnk+CCcqEPEaQAN9Xd+HJ19lXs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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