SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '16cb051474377a97f6abc222648739037c1b8e421a05d1d1e560392e3d14b123' 
  AND token = 'SVP4ViAfTtLyUG0zDMlyjF7W3XvSf9jPd7hA0Znz1RI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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