SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'eac621685a8058988223bec1a4ec554042c573dd8b6cc0ce1f372420466671f1' 
  AND token = 'Ix6mrbJXlpl1lolen5UxHXGhKDfCbuWKTmsiYwPvnho=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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