SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'eba7ffb0e40ccb9e83b149077c1a336dae87684a7af9c6185ac5c62f1ae85f42' 
  AND token = 'B+PXxVCnwFMxdp+dYDKjrCWa6r4/rvd0cfjl8ZV0Xz8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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