SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d8914852d49ec3027e422fd1cf504e3b2174c86189065deefd838302bd0c64b' 
  AND token = 'o26AqwWNYSSIemkDpFHKIsiK6EVgMjOMsgKfpF00a3o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00082

JSON explain

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