SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12b4ce0e64ddf4b2209fd9e05688a51fb3a16170668d6fae2e3736aaceb2400c' 
  AND token = 'ULV3q5RwrC+vjw8nZUxMPhGkphMlGSNYqj/acyZkKjk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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