SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '567bc84cf78afbc4575d293879f68df75a8e5a5e8de453ea72b4462c39c21531' 
  AND token = 'ZnwwHPHZG2KcFUmTLy5QzrvA7589+vdDbUBYQKHpLNs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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