SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1ad9cbd30417c0d483efb712ef517c45e3ec9d7c00ec92814854bbdeec4b3839' 
  AND token = 'JaJPqF51ChInQRyDT/B5vrIt6r8egwWChVVynYN6mD4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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