SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '62bab73aa4dd87cc62d3f5cb33e641211e3357748c232d8c0918a68817add480' 
  AND token = 'WQDeyhJZWJ29xrm/khJliUg8lxMVqyu5xhwmvv7RYdU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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