SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52d86a7f137ac5a4fcb0cd626d106ef651c32748fbea122d3650a69e333980b5' 
  AND token = '0kSFrEgvvwQuuH+kLj9JE4mBePtC2Z8ssweh+9/L+MA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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