SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0c5bd339651511af2eae21f255304dd1530fd320a92d087037f515a155a2d95f' 
  AND token = 'S6tnSuLMYQYSnB2yXTNWzqwFt9eHOB1D/9d++jeWcck=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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