SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9945ced98871162db3e856c82b4d019e0c0726608d3af09f9945e4afd000c37d' 
  AND token = 'atQAImn758DDyMT9EtE+hyJeoik+H1ZqtrTtedk7YiE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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