SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '6b2c80a8ebf1d039a77fb88044f32b0efcc2f75fefa97859f74b159df1576e5f' 
  AND token = 'cvjM//Pf4t/duwrIObslIQZV8VRzq9DvQMJ/ljFZ7sc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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