SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9ff50e43cb0e0d99e7af17061bf227b9623a9c3b56dcd3101d8a685222884226' 
  AND token = 'sJYby1+4IwsI4Iofrj2RHckZHshXq993JcZMKL/cvLU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}