SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'e8cb41eb34e20e66d9c6fd8694767430cb3fe8210c40482e1d8ba312253d7c49' 
  AND token = '31XtVS93DUO5b5DmqMDgCXrEhrYZup7QwoK4YTQLkPY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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