SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc96aa38a3559460ddf3d72d4bce7863d40732816ac3ac87cdc840e1a371faa4' 
  AND token = 'nnjzxfkL3RqmW5iEKudTd2HaPYdC7KVDztx8s/yFfpw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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