SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b67cf657cf2f95c0e59981dfd9375161982905ce6807153f8f79cb969ceefb51' 
  AND token = 'ADtOd//woMRm+u9LANsNfzZzUzH+scKe5SG9E3jdQpg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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