SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cc761d1b3124c22df485d123dc0fd78653b61f65717db41f964636df9a4a1988' 
  AND token = 'XzwpBEj3ZpdQyuQY3lL7ocKM5Kd/HuEmEGRCFcWRSkg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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