SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b56df85530d56a4d4c3a7820190bcb14d1d3c88e681ba231653e7e02ecb6150' 
  AND token = 'LP3yIrjegzh8tLOr/rH0/sh5t+UnceQTzwULKjTROIc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00009

JSON explain

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