SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e68410b9175789e3a39be7ccdb960d4e479e7dd920f5c8befdf50672c48c1ed8' 
  AND token = 'E66arQCXmBWTIn2nOtd+lAwXxuQrErARFGRmaFFUWtI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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