SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'a9c729caf53ceeb2af09043e418a67291035e9304d68f1e2fa9e0a75c17c2198' 
  AND token = 'sTtJExTtYhq0FNbH5b+ji/Ma4l5fUKr6PcgW0acmVJ0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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