SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e735bac99e71d5204ef6fdda7a62bb2b9720c846bb7172434cb78b151e33a1d' 
  AND token = 'qnRiq5fMOkMEizQBG0UVLjzOaCEmsrJQxO6Y8Q78ALw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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