SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd2457827952228ce4a5c0251c181be0cb489abd192f82855bb48965e40e7f51b' 
  AND token = 'CYiCWIfRuhKiqXk+Aa0AyIkfHWcGlbejQ+Vsf+ZNnXg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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