SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4aa55063c44e238f78436e4b1f08fe82effc8d186584b2cfaf2f5c8313de47eb' 
  AND token = '2yq6T/A/l9BupbwEG8eswf6fVRh0xn0zZxFF+5iXjkM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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