SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3891fa3dcdbbb5f81b864ac2101fdbf43a6c37f81b33bd84de729bb22ce8e40f' 
  AND token = 'Wq7jt8dspauB0Tkp12OOgmDDs9hK07pQXW5cGU6Wt1Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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