SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '5615e3e1c788022367a92b5456ec4ce8a9ce5a9b37af8c29f0f1b815093567bf' 
  AND token = 'hRoeGPZ7R9V7boU2nVxJrCkUR3ijlHnGVfqr6dH6VJY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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