SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b53f6a4919e8a9bf36fb0a9f4416aefb6103e32944888efa7677855fdbf4c9e0' 
  AND token = 'Kg78/haQW7Naxbbgy2VQlLs9qKWHGXBz8DVYj6gzdnY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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