SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b54abd86621f1f9a67d61d7f7599afa5bb6757dda8908f18fa4876a15d2061fa' 
  AND token = '9uTvES/l0qag+QilwxUoPDQ7zknhzmgZhAHd1Yj+shI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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