SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd8b0a4af765c7312b32ee89990a587999cf98866d3d5bff9058faf2d2b1f5d5d' 
  AND token = 'vSjv1J6/OZ4QWm5K83Tshu9S6jzI0Q/xw1+nkF+W3co=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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