SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'da4e61ad94c35c09e29b33c172ceddabe5f2e57cbd644136fcc3ad88a0022451' 
  AND token = '3/7hHf4ZG2WPydnQ0YOf7kHCjkWHfLpLDCM+51petI4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}