SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '621bb983dec753c9156c0fa873eba6575b2234a7d20b3ba445ac596999bbce9c' 
  AND token = 'eqr8lzdh3M8EHkyPdlKq7yuzMOj6LTO17X0+6VUDi8Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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