SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '9d93b55ac545c105209d48474b411d6e10b3f3a39bf46b9d53e06e9d16b197ec' 
  AND token = '0CYZoOxDl98uWB/XoVpqtHKuXiFZdfe0xO9vFfYPnGI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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