SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '61c9421b27eff5d90d46ca1338ba92ac2f9cf1d331e5ad4c6b881ef4b5e0e2ce' 
  AND token = 'yvQ9qVGZ4TcBOHt14cJ+LSicNVOgMSjEJfwE3j92ors=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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