SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '321efb7aea6d8d6b3d391a85f3c4eb32103dca7a402fac7479825c13f7bece47' 
  AND token = 'OQXdbwZNdDtsrVq24hIGYiFzf+wTD/ZFaIg8InrPn4g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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