SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3ab9611e4971beb7d54412211a0df2141dc7f261192488dbed9a52c9508f394b' 
  AND token = 'PAsf9Enk0DnohlPp8KVJgZ0G/SdGRZqQbVUk9yvHWqg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00061

JSON explain

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