SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f09fb9ecd88a7ca2a4a0e99a1ad34fd6a92681e024529e6ff4dce45b8af5869d' 
  AND token = 'BXkMaMQeEANtc1xpDwQqHSkwbUHSKPTMddawKh9AQrk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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