SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '411a5cce609421e7991c2971bce1c6d6499651081c92991333daa2a10195dbf4' 
  AND token = '8SwgDoJeqWat0qLKbTqI9+XKQRQkzp8Mo4lCIIiXcHs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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