SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a64180e7056582e74b697198577337fd3ce4fcd9cc0440206d7118eb597539c3' 
  AND token = 'KUtSmAYl28SoGBob7EXHghFUZVOYoUdzKtkFEuk2FRg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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