SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4e69ec9a98575d11f9c2fcf6566f0f8fcb845cf3e20b8d512ca8ff71c2b39e53' 
  AND token = 'KxxRo5eyTAuILyO1MIbZCTtloLDAUmMMNE/BNIZm3xI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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