SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a6a20dabbe89b4e80475e68e296a0635a5fb716363f084127308f9c279564f2' 
  AND token = '/HqUSRxtvqJear3iNdnPvTkyHviA8/jgCQdbu9l3lWY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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