SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3c863c611544b2b774ba984327cacea0be4b81dc47a11191b3acd04183e6ce02' 
  AND token = '0y5TPHDcfnfiNueZBjsBJbSHrzPTK1UAyuis/xiN1SE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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