SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4929db55f23835dc0cbf8397aa4962c76d8ed78528f74781a7db9f64d27f1aa6' 
  AND token = '3sGgYPq0X3XwrKrQPOnKxdk47MBWPVfgZ+ZfuyZGHNE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00063

JSON explain

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