SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ed04728783bfa33d5f3ce9168aefd340f1158e4bdbc665458cea22ec2746e09' 
  AND token = 'JewGnwgz8A32QcOtllztFt4/QRdSNpfdQkjQEZADBys=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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