SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e5e6b35a96599ceba971566efbaa2c01fa5339d852dcbb1c76344f12d817a0d0' 
  AND token = 'UWIwqs0L0BgY9aNyJxGsVIdTQyVwa/rZQchBFCRoa6w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}