SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '973fcb18ae89f7c17aabd8006eccbe44dc3af919f284f158fa20f27c2cb13541' 
  AND token = 'n1BAOlsN51GxZrzDgLYwIjpkS9wRgOGkMTEX2shWmzw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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