SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '10446ae6e240fce5dfd8a5a28aeb7bcf381eb88b9251bf88c595aacd88633733' 
  AND token = 'HAVtZD3ks42KCtjC3qu6G2Ys/dB0hULLMJF0JYqzenA=' 
  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"
    }
  }
}