SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ab721d2d11452ff4b84e19f6b473fcc86b28dba0ca78efc4cf51386ff7c33ccf' 
  AND token = 'ga+1fpXWJj8tkvw6oKOAFVvfjatdC9tdy5+V4FvlT9U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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