SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '9465851f4f0bae06251847f08de05e64b813b040032d9aee9442d4ddfb16c391' 
  AND token = 'bss4j6kzbTj7CTm9RLLAAOYmTsX/KgXjYZKUiwM0/r4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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