SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b8b6479b7b5ff9c1a7fd861a70dabddc513b3674f85ed0a37a1753aef3e521a5' 
  AND token = 'GACZoYd5UylmWluwXLciLrXfmtBVS3iXMXmUJBM1K3M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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