SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd81a0c80614171d14a41be5de85208d4a31ce009d3013e8347cacfba4971237' 
  AND token = 'rIadIXCOIWTJ4hOxGTyKI+kKtjfiaIKzwQcxmKWwcU0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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