SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '748f522de261bb11182a12c20dd7d6a664723eb8760059ed090c07dfeaf616f8' 
  AND token = 'fUatS+oYOvgQBGSCNj794wIJiiSPioUFRbP3o2oI774=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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